Knurling apparatus



Jan. 25, 1955 s. P. WATKINS 2,700,314

KNURLING APPARATUS Filed Aug. 4, 1949 3 Sheets-sheet 1 I lo INVENTOR.

\ STANLEY P. WATKINS HIS ATTORNEY Jan. 25, 1955 s. P. WATKINS KNURLINGAPPARATUS 3 Sheets$heet 2 Filed Aug. 4, 1949 STANLEY P WATKINS BY 2 7 zy HIS ATTORNEY s. P. WATKINS KNURLING APPARATUS Jan. 25, 1955 3Sheets-Sheet 3 Filed Aug. 4, 1949 INVENTOR. STANLEY P. WATKINS HISATTORNEY United- States Patna KNURLING APPARATUS Stanley P. Watkins,Baltimore, Md., 'assignor to Armco Steel Corporation, a corporation ofOhio 1 Application August 4, 1949, Serial No. 108,461 7 Claims. c1.s-s.1'

My invention relates generally to the production of knurled metal wirestock, and particularly concerns both a new method of knurling stainlesssteel metal wire stock, and a new apparatus for effecting such knurling.

An object of my invention is to provide stainless steel metal Wireproducts such as nails, staples, and the like, which are of highlysatisfactory holding qualities.

Another object is to provide a method of producing knurled wire stockwhich is characterized not only by its basic simplicity, but as well, byits rapidity and effia ciency, by the small number of operational stepsrequired, and by its certainty in operation and in results achieved, allin the substantial absence of skilled supervision.

A further object is to provide an apparatus of the general typedescribed, wherein effective knurling of stainless steel metal wirestock is provided,with desiredpattern thereon, which is characterized byits simplicity, its small number of moving parts, the sturdiness andreliability of all such parts in operation, and by its basic economy,both as concerns initial cost, and in subsequent operational andmaintenance expense and upkeep, and which functions, inthe substantialabsence of skilled supervision, at high operational speeds, and thiswith certainty of results, and which, at the same time is characterizedby long, useful life with minimum interruption from break-down.

Other objects and advantages will in part be obvious and in part morefully pointed out hereinafter during the course of the followingdescription, taken in the light of the accompanying drawings.

Accordingly, my invention may be seen to reside not only in a newproduct but in the method of producing this product in matters of theseveral manipulative, procedural and operational steps employed and inthe several parts, elements, mechanisms and features of construction ofthe apparatus and equipment employed, the scope of the application ofall of which is more fully set forth in the claims at the end of thisspecification.

In the drawings, wherein I disclose that embodiment I of my newapparatus which I prefer at present.

Figures 1 and 2 respectively are side elevation and end views of myinvention; while Figures 3 and 4 respectively are side sectional andtransverse sectional views of the apparatus of Figures 1 and 2;

Figure 5 is a perspective view of one of the flange sep-' aratorsemployed in my'apparatus;

Figure 6.'is a perspective view of'one of the work rolls of theapparatus;

Figure 7 is a'persp'ective view of one of the yokes, for supporting theknurling rolls of my apparatus;

Figures 8A and 813 respectively are side and end views of one of thepressure blocks used in my apparatus for forcing the roll-yoke" andknurling rolls against the wire sto'ck;while Figure 9 is a perspectiveview of 'a counter-weight lever and associated counter-weight, forimpelling the pressure I block of Figure 8 into working position.

Throughout the several views of the drawings, like reference charactersdenote like parts.

To facilitate a more ready and thorough understanding of my invention,it may be noted at this point that as yet, stainless steel products haveby no means received the Widespread acceptance in the field of fasteningdevices, such as nails, brads, clips, staples or the like, to which theyappear to be entitled. And this is true in spite of the fact that itwould be expected that the basic are driven.

qualities of these products would admirably adapt them for use in thisgeneral field of production. For it has long been recognized that thosematerials which are in present day use in such manufacture as nails andthe like possess certain inherent and characteristic disadvantages whichimportantly reduce their acceptability for such purpose.

Illustratively, it is well recognized that to adapt ordinary carbonsteel wire to the production of nails, brads and the like, particularlythose intended for outdoor use, this carbon steel wire stock must firstbe subjected to a galvanizing process. Not only is this expensive andtimeconsuming, requiring as it does, an additional operational step, butas well, fastening devices formed of this material are observed to faultin a number of different manners, as chipping or scratching when beingdriven, leaving spots or portions of the device open to corrosion withlater rusting, and the consequent formation of unsightly rust spots.Particularly are these disadvantages observed in the case of roofingnails, employed for example in holding tile, slate, composition roofingand the like. And, as well, in the case of ordinary headed nailsemployed for holding down external siding, sheathing, shingles,clapboard, and the like. Similarly, in the other long-employedexpedient, where nails are reproduced from copper or bronze wire stock,it is observed that with the passage of time the characteristic greenoxide streaks are encountered, discoloring and marring the architecturalsurfaces.

Now, from the standpoint of resistance to wear stainless steel is anadmirable material from which to construct such fastening devices. It issturdily resistant to substantially all atmospheric attack. Elevatedtemperatures, with or without a high degree'of humidity, extremely lowtemperatures, icing, the soot and dirt of the city, and the saltyatmosphere of the seashoreto all of these, stainless steel issubstantially impervious to attack. Moreover, it has a pleasingappearance. So far therefore, as concerns appearance, immunity toatmospheric attack, and longevity in use, stainless steel possesseshighly advantageous qualities.

I find, however, that with repeated wettings and dryings of the roofing,siding or the like under the weather conditions encountered, thesefastening devices fail to hold after a short time. This, I attribute toa slight rotting or softening of the wood, or product into which theyWhile such rotting or softening also is undoubtedly encountered with theconventional nail, brad or other fastening devices, these neverthelesshold very much better than the stainless steel nails. And it is mythought on this that there is some accompanying rusting or corrosionwhich serves to lock with the wood or other product and compensate forthe loss of grip arising from the rotting or softening. Of course,however, as noted above, there comes a time when the one, augmented bythe presence of the corrosion product, exceeds the other and thefastening fails completely. 7

Thus consider the nailing down of roof shingles. The nails used for thispurpose commonly are about an inch in length. Yet they are required andare designed to hold the roofing securely in place while at the sametime stopping short of completely piercing the underlying sheathing.Despite this short length and despite the small depth to which thesenails penetrate, they are required to withstand not only the liftingpressures of accumulated ice and snow, but as well, the lift of highwinds and the expansion occasioned by heat and cold. Ordinary nails" ofthe type generally described at first, and when initially installed, aresatisfactory for this purpose. Failure of the galvanized coating in thecase of coated carbon steel wire, however, and the passage of timealone, in the instance of bronze and copper wire, will shortly give riseto detrimental staining and rusting and eventually will be accompaniedby mechanical failure. If recourse could be had to the use of stainlesssteel stock, these disadvantages would be suppressed or entirelyavoided. But I findthatstainless steel fastening devices are notacceptable for this purpose.

Accordingly, an object of my invention is to overcome the inadequaciesof the prior art and provide fastening devices of stainless steel whichare strong, tough, corrosion-resistant and yet well adapted to strongyhold under (h G the various conditions encountered in actual practicaluse for great lengths of time. And a further object of my invention isthe provision of apparatus for imparting holding qualities to stainlesssteel wire stock.

And. now referring more particularly to the practice of my invention, Iimpart to the wire stock a particular surfac in fact a knurlingcomprised of uniform indentation of the stock by a multitude of smallimpressions disposed in a sweeping spiral of wide pitch. 1 find thatthe. metal bordering each such indentation is, slightly raised above thesurface of the metal, due to the 'flow of metal created by theindividual indenting elements, enhances the holding effect. In otherwords, I thereby create a roughened surface imparting substantiallyimproved holding power. Viewed from another angle, the holding effect ofmy new product is achieved in threefoldimanner. First, by the existenceof the slightly raised borders of the indented portion, .second, by theindentations themselves, which permit the entry of the material intowhich they are driven, 'into their numerous interstices, and third, bythe effect of the spiral, which, to a certain degree at least, acts as asort of flattened thread of 'wide pitch, say about one turn to an inch.

While many modes of generally achieving knurling are available, andalthough many apparatus and 'machines exist for imparting knurling towire stock, I find that for one reason or another, these methods andavailable apparatus are unsuited for imparting knurling to stainlesssteel stock wire stock. Accordingly, I have devised a new method andapparatus.

, Thus referring more particularly to the embodiment of my apparatus asshown in the several views of the drawings, it will be seen (Figures 1and 3) that my new machine comprises two fundamental parts, namely, afixed or guide part, and a second or revolving head part. The functionof the guide mechanismis to lead the wire stock to the revolving headand to make the same available to the revolving head in accordance withthe demand of the latter. At the same time the guide rolls serve toclamp the wire stock firmly against, and to resist completely,

all tendency of the wire stock to twist about its axis under theinfluence of the knurling rolls of the revolving head. On a suitablesupport common to all parts of the new machine, I provide a housing 11,in which I mount suitable paired guide rolls 12 and 13 (Figure 3). Bolts14 serve to hold down the housing 11 against the base plate 10. Theserolls are disposed with axes parallel to each other, and transverse tothe axis of the metal wire stocklS, Figure 3. The guide rolls 12, 13 aregrooved to permit the passage of the wire stock, and the size of thesegrooves is dependent upon the diameter of the wire to be processed. Whenthe size of the wire is to be changed materially, then the guide rollsare changed to ones having width and depth of groove closely conformingto that of the wire stock now to be processed. Where the change in thewire stock is not appreciable, no such change in guide rolls isrequired. Suitable bearings, conventional in the art and not here shown,are disposed in the housing 11, and carry the rolls 12, 13 for idlerotation therein. Thus, the rolls are so designed as to be free, torevolve as the wire is pulled through the machine. No power or drivingimpulse is imparted by the guide rolls.

In the present embodiment the lower roll 13 is fixed asjto its verticalheight. The upper roll 12, however, is

designed so as to be raised or lowered, for convenience in feedin hewire throuch the grooves in the wires. or for controlling the pressureof the rolls on the wire stock. To this end, I provide a threaded rod 15and handle 16 for raising the upper guide roll 12. It is ofcou rseentircly practical, where desired, to construct both rolls for verticalmovement. For all practical pumoses, however, it is sufficient only thatthe upper guide roll 12 be susceptible to raising and lowering,The-function of these guide rolls 12, 13 is two-fold. Firstly, theyguide the coil of wire to the revolving knurling head to be described.Secondly, these guide rolls securely grip the wire stock so that itcannot turn about its axis and twist after introduction into theknurling head. The necessity of this restraint against twisting is aparent when it is considered that the action of the knurling mechanism isto twist the wire progressively as the latter passes through theknurlingh'ead. Thus, without the restraint resulting from the grippingof the wire stocksecurely-between the guide rolls, in the grooves of}the latter, the wire stock, as it. is fed-through to the. knurling headand" advances in 4 its passage, is found to become severely twisted, andin many instances badly snarled and kinked.

From the guide rolls the wire stock is drawn into the fundamental partof my new machine, the revolving head. This revolving head is indicatedgenerally at 17 (see also Figure 4). This head is a composite mechanismconstituting in part two parallel disc-like plates 18 and 19. The plate18 is disposed adjacent the guide roller housing 11. It is fast .onaspindle 20, which itself is mounted on a standard anti-friction bearing21, such, by way of illustration, as the bearing now available on themarket, as Dodge Type 'SC. The bearing 21 is removably carried, bysuitable means as lock-down bolts and nuts 22, on a standard 23 Weldedor otherwise made fast to the base plate 10.

Spindle 29, which is hollow (Figure 3), and has a constructionhereinafter described, is termed the wire inlet spindle for the reasonthat, being adjacent the guide rolls 12, 13, it first receives the wirestock into the revolving head 17. Similarly, the face plate 19 iscarried on a spindle 24 which is turn carried in a suitable antifrictionbearing 25 similar in type to the bearing 21, and iusimilar manner ismade fast by suitable removable and releasable hold-down means, such asheaded bolt 26, on a supporting '.pedestal27 carried on the base plate'10. Thus, the spindles 20 and 24, together with the head plates 18,19,arerevolvable in the bearings 21, 25. The spindle 24, hollow in mannersimilar to the spindle 20, is known as the wire exit spindle, for thereason that it is located on that side of the revolving head which isremote from the guide rolls 12 and 13, and accordingly is that spindlethrough which the wire stock last passes in its passage through therevolving head.

As I have stated, these spindles 20 and 24 are hollow in an axialdirection (Figure 3), and I provide hollow inserts or guides 20A and 24Atherefor, which are interchangeable amongst each other, and which havecentral passages of different diameter,-for the accommodation of wiresof different sizes. The center line of the hollow portions of the guidesis set on the exact axis of thespindles 20, 24 so that the hollow guidesserve to align the travelling wire 15 in the exact center of therevolving head 17. Conveniently, these guides, termed respectively inletand exit guides, depending upon which spindle they are located in, areformed of hardened tool steel, the better'to withstand the abrasiveaction of the rapidly moving wire stock.

As I have stated, the plates 18, 19 are here attached directly and madefast to the spindles 20, 24 or are formed as integral partsthereof. Theycomprise two circular head fiangesand form the 'side of the circularhead and provide support for the working parts of this head. Metalseparators 28, 29, best shown in Figures 1 and 4, serve to separatethe-head flanges 18, 19 at proper working distance from each other.Although these separators 28, 29 may be of any desired shape anddimensions, they are here shown as being of segmental shape in plan,having an appreciable massand thickness, and being approximately 2%inches wide. They serve, as best shown in Figure 4, to separate thecounter-weight levers and pressure blocks, later to be described-at aproper distance from each other.

The moving parts comprising the mechanism of my new apparatuscomprises anumber of essential elements which effectively cooperate with each otherto achieve the desired operation. Having referencev to Figure. 3, itwill be seen that the wire stock 15 emerges from the hollow guide20A'within the spindle-20 into the path of the work rolls, here shown at31, 32. These work rolls are carried on suitable bearings '33. which inturn are carried in work roll yokes 35. These yokes are carried' bypressurewblocks' 36, which in turn, are forced in a generally radialdirection inwardly towards the" wire stock, We counter-weight leverindicatedgenerallyat '37 and the. centrifugal action of which iscontrolled sensitively by means of a cooperating counterweight '38.

The spindle 24 is extendedv through the bearing 25 and terminatesexteriorly thereof on the outer side thereof. from the head'flange 19.Suitable means are provided for powering thepower shaft thus provided bythe extended spindle 24. While this may take any suitable andconventional form. such as gearing or the like, I here conventionallyshow the same as comprising a pulley 39 having a V-shaped groove 41)therein and'whichpulley is made fast to the shaft 24 by suitable meanssuch as a set screw 41; It is by no means necessary that the groove 40'-he of V- or A-section but it is here so shown because of the improvedpower take-off properties inherent in pulleys of this general type. Anysuitable means may be employed for powering the pulley 40, but as hereshown, this comprises a belt 42 shown in Figure 2 which is impelled by asuitable electric motor 43, the base 44 of which is carried on thecommon support 10. Conveniently, this may have a rating of one-thirdhorsepower, capable of operating at say 1725 R. P. M.

Considering now more particularly the revolving head 17 (see Figures 3and 4), the working rolls 31 and 32 are conveniently formed of hardenedtool steel, having illustratively, a hardness by Rockwell test, C58-60.As perhaps best shown in side elevation in Figure 6, these rolls maytypically have a one-inch diameter with an approximate length of one andone-half inches. Thus they have generally the shape of an elongatedcylinder. These dimensions are not extremely critical, and the sizes maybe increased or decreased within reasonable limits. It has been myexperience, however, that rolls of smaller diameter do not function aswell as the larger rolls, they tending to throw off center the wireundergoing treatment.

- In the typical embodiment disclosed, I mill the work.- ing surface ofthe rolls 31 and 32 with rightand lefthand grooves. These grooves I formin the shape of sharp Vs, using for that purpose a 90 cutter. I disposethese rightand left-hand grooves so that they will cross in such manneras to form sharp, diamond points. Further, I dispose the grooves so thatthey will possess an 0.038 inch position normal to helix and with athree inch lead, having a 573l helix angle. Conveniently, I cut thegrooves to a depth of 0.019 inch. Of course, however, other types ofgrooves may be employed, for achieving a variety of different patterns,all falling within the ambit of my invention.

In the foregoing I have described how the rolls 31, 32 are mounted insuitable bearings, and are thereby carried for rotation in the yoke 35.This yoke 35, details of which are shown in Figure 7 is one of a pair ofsuch yokes, there being one provided for each work roll 31, 32,respectively. Each such yoke 35 comprises paired and parallel extendingleg portions or cars 39, 39; and each such ear portion 39, 39 bears, ona common axis, holes 40, 40 for the reception of the spindles 33, 33 onwhich the work rolls are mounted. From the central web 41 of these yokemembers 35, 35, there extends axially and centrally, and rearwardlythereof, a spindle 42, made fast in any suitable manner to the bodyportion of the yoke. Now, this pin is disposed perpendicularly to theaxis of rotation of its cooperating work rolls 31, 32 and it rests in arecess in the adjacent pressure block 36. The rotatablenature of the pinor spindle 42 permits the yoke 35 to be rotated as required, in order toadjust the angle of the work roll 31 relative to the wire 15 beingknurled.- To this end, I provide a recess 43 diametrically across, thefree end of the spindle 42, to participate in the angular calibration ofthe work roll yoke 35.

The pressure block 36, as previously noted, is'disposed between theworking end 45 (Figure 4) of the counterweight lever 37 and the head 41of the yoke 35. This block 36 is of the form shown in Figures 8A and 8Band has a central opening 46 passing through the body portion 47thereof, for the reception of the spindle 42 of the roll yoke 35. Eachpressure block 36 has in addition to' the body portion 47 thereof, anupper, winged portion 48 which is both outwardly and laterally flaring,as at 48A, and is rearwardly extending as at 48B. The overhang thusprovided serves effectively as a bearing surface against the bottomfaces 28A and 29A of the cooperating flange separators 28 and 29. Aretaining pin 49 (Figures 3 and,4) extends between the adjacent headflanges 18 and 19 and serves as a bottom abutment for each of thepressure blocks 36. The contact then of the upper surface of the planeportion 48 of each pressure block 36 against the bottom face of theflange separator, and the contact of the outer face 47A of the bodyportion 47 ofthe pressure block 36 against the working head 45 of thecounterweight 37, and the contact of the bottom'face 47B- of the bodyportion 47 of the pressure block 36 against the pin 49 cooperate tomaintain the pressure blockin its proper and operable position.

'- It is apparent (see Figures 7 and 8B) that the spindle 42 of the yoke35 is longitudinally movable in'the open ing' 46 provided in thepressure block 36, and that as well, it is rotatable therein.Accordingly, this permits adjustment of the yoke 35 and the particularroll 31, 32 carried thereby within the pressure block and relative tothe wire stock 15. In use, the roll is first adjusted to the properangle for optimum knurling (Figures 1 and 3), and like wise is movedbodily relative to the pressure head (Figure 4) so that in operation, itwill bear against the wire stock to the desired extent. Two adjustmentsare thus seen to exist, one rotational, and the other lengthwise.

To facilitate the rotational adjustment, use is made of the recess 43 inthe free end of the spindle 42 (Figures 1 and 7). A screw driver or thelike is employed to rotate the spindle 42;-and to facilitate nicety ofangular adjustment, the outer vertical face of the pressure block bodyportion 47 is'inscribed as at 47C (Figure 8B), so that the diametricallydisposed recess 43 will line up with the said graduations 470 as thespindle is rotated relative to the pressure block 46. Similarly, toobtain the longitudinal adjustment, the yoke 35 is moved back and forthin the bore 46 within the pressure block 36 until the proper adjustmentis achieved. At that time a lock nut or set screw 50 (Figures 4 and 8A)is threaded down through the side of the body portion 47 of the pressureblock 36 until it is fast against the spindle 42. In this manner, therolls 31, 32 along with their supporting yokes 35, 35 are made fastagainst movement and in operating position relative to the wire stock15.

It will be seen from the foregoing that because of the constraininginfluence of the faces 28A and 29A of the flange separators 28 and 29respectively and the retaining pins 49, the pressure blocks 36 areconstrained to limited movement in a horizontal and axial direction asshown in Figures 3 and 4. This horizontal movement is controlled by theworking head of the control lever 37 under the influence of thecounter-weight 38. Because of the latitude in machining which may wellbe required in the design of the pressure block 36, I provide between itand the head of the yoke 35 a suitable shim A formed of steel, andfitting loosely yet nicely about the spindle 42 of the said yoke 35. Thenumber and width of shims may be varied as desired, in accordance withexperience.

Pressure block 36, as also previously noted, is under the control of thelever 37. This lever has elongated arc-like or crescent form and ispivoted near its working head 45 on a shaft 52 (Figure 4) which extendsbetween the head flanges 18 and 19, being received in a facing portiontherein disposed slightly below the horizontal center line of theapparatus in the case of the left-hand lever 37 in Figure 4 and at anequal distance above the horizontal center line of the apparatus in thecase of the righthand lever 37 as shown in Figure 4. As best disclosedin Figure 9, this counter-weight lever 37 has a hub portion 37A which isof substantial width, and which at the same time is less than the spaceprovided between the head flanges 18, 19. At its head end thecrescent-shaped counter-weight lever 37 is bifurcated into forked headportions 45A, 45B. These bifurcated pressure arms bear against thepressure blocks 36, 36, against the recessed faces 47A thereof, andtend, when the revolving head is in-motion, to force the pressure headyoke 35. and work roll of 31, 32 against the wire stock. Washers 53, 53(Figure 1) are disposed about the shaft 52 between the counterweightlever 37 and the head flanges 18 and 19, soas to avoid tendency towardslateral movement of the counter-weight lever 37 across its supportingshaft 52 and consequent frictional stresses attendant thereupon. A setscrew 54 serves to make the counter-weight lever 37 fast on the shaft52.

Each counter-weight lever terminates in an elongated curved or crescentshaped blade portion 37B on that side of the pivot point 52 opposite theworking head 45, 45. thereof. This portion 37B of the counter-weightlever terminates in a slanted, plane face 37C (s ee also Figure 9) whichis adapted to abut against but to be freely movable relative to :theadjacent face of the flange separator in Figure 4. Each counter-weight38 is made fast by means of a set screw 38B at an adjusted positionalong the length a of the counter-weight lever arm 37A. To facilitateadjustment of the counter-weight along lever arm 37A so as to setthe'same according to given pr ssures ofthe work rolls at specific ratesof rotation of the entire working head, suitable inscriptions 37D areprovided along the length of this crescentportion 37B.

Asdisclos'ed, the counter-weight 38 has an internal bore 38C ofrectangular section complemental to the cross sectional contour of thecounter-weight lever arm 37A. This constrains the counter-weight againstrotation about the lever 37.

It is apparent from the foregoing (see also Figure 4) that the severalworking parts heretofore described exist in pairs. For symmetry and forequalization of stresses. and strains, the elements of each pair ofworking parts are disposed in generally diametrical opposition to eachother, on opposite sides of the revolving head. This construction issuch that when the working head rotates about its axis on the hollowspindles 20, 24, the countenweights 38, 38 are thrown outwardly bycentrifugal force. The pivoted lever arms 37, 37 transmit this impellingforce couple, through working heads 45, 45, inwardly against thepressure blocks 36, 36. This inward force is transmitted directly to theyokes 35, '35 and thence to the working rolls 31, 32. These workingrolls are thereby forced with considerable pressure against the wirestock which passes between them. The pressure, the adjustment of whichmay be varied by the position of the counter-weight 38 along the arm 318, by the width and number of shims 50 between the pressure block 36 andthe yoke 35, and by the longitudinal and rotational adjustment of theyoke relative to the pressure head 36, is sufiicient to bring about thedesired indentation of the wire stock.

The skewed position of the rolls 31, 32 is sufficient to create a spiralknurled pattern on the wire stock. Moreover, the pattern of the knurlingrolls and the skewed position in which these rolls are mounted serves topull the wire through the machine as an incident to rotation of therollers. In other words, the knurling action brings about self-feedingof the wire stock.

I control the rate of the feed of the wire stock by the control of theamount of skew of the indenting rolls, and by the rate of rotation ofthe working head (the speed of the motor 4-3 and the ratio of drivingand driven pulley diameters). I find it entirely feasible to vary thedegree of skew in accordance with both the indenting pattern desired andwith the desired pitch of the spiral pattern. Typically, however, Iachieve excellent results when the knurling rolls are set at a skewangle to the axis of the wire stock of about 42 /z. Changes in thisangle vary the pitch distance, and opens or closes the indented pattern.as desired. In this connection I have achieved successful knurlingwithin a skew angle range from about 10 to about 80. I prefer, however,that the skew angle be within the approximate range of about 40 to As Ihave stated hereinbefore, the spindle 24 has fast thereto the pulley 41connected by bolt 42 to the electric i motor 43. This was stated,however, as being merely typical, and I further suggested that anydesired and conventional system of rotating the head 17 could beemployed, as desired. Moreover, this head may be rotated at a variety ofspeeds, provided only that counter-weight adjustments be made to insureproper working pressures. illustratively, I have found a rotationalspeed for the work ing head of 3500 R. P. M. to be satisfactory for themachine undergoing description. At this speed and under theseoperational conditions, I find roll pressures of approximately 1000pounds per squareinch to be necessary to indent fully, cold-drawn steelwire of composition l8 parts chromium to 8 parts nickel.

In the practice of my invention, and as more clearly illustrative of themethod features thereof, 1 provide coils of stainless steel wire stock,placed conveniently on a take-off reel. Preferably, I lead the wirestock from the take-olf reel through a lubricating bath to minimizedeterioration of the guides. Very little lubrication is required. and ifdesired this lubrication may be dispensed with. However, I find'that theslight film of oil pro ided on the wire stock by wiping the wire throughone or more folds of felt or cloth is helpful in reducing deterioration,and in prolongiru appreciably the life of the apparatus. Thewirestock,thus lubricated. is then fed through the inlet groove of the guiderolls 1!, 13 into the orifice of the inlet spindle guide 2% and thencebetween the opposed and skewed knurling rolls 31, 32. Thence it passesthrough the exit spindle guide 24 to take up reel, not shown.

Once the wire has thus been led loosely through'the machine, and beforethe revolving head hasbeen'set into rotation, the guide rolls 11, 13 areadjusted by tightening down the spindle 15 (Figure 3) by the hand wheel16. In this manner the wire isgripped firmly in the central groove ofthe guide rolls sufficiently tightly so as to restrain the wire stockagainst twist, but not so rigidly as to hamper the free longitudinalpassage of the wire stock through the guide rolls. The working rolls 31,32. are skewed to the desired angle by adjustment of the yoke spindle 42through its recessed head 43 relative to the graduations 47C present onthe pressure block 46, making use of the engraved lines on the base ofthe yoke pin and on the back of the pressure block. In this connection,care must be observed that the angle of adjustment relative to the axisof the wire stock E5 is the same for each working roll 31, 32. For ifthis is not done, the forces exerted by the opposed rolls 31, 32 willnot be equal. Not only will a distorted pattern be obtained on the wirestock, but moreover, the wire is subjected to uneven strains resultingin distortion of the wire. strains becomes aggravated by the degree ofdiscrepancy between the settings of the two knurling positions.

Nextly, the counter-weights 38 (see Figure 4), similar in weight anddimensions, are set in like positions on their respective lever arms37.3. The motor 43 is started into operation and the head 17 is rotatedat desired rotational speed, typically 3500 R. P. M. .As thecounter-weights 38 fly outwardly, carrying with them the crescent-shapedlever arms 373, the counter-weight levers 37 rotate about their pivotspindles 52, so that the working heads, 45 thereof bear, by theirbifurcated portions 45A, 45B, in the recesses 47D, 47D provided in thepressure block 36, andforce the yokes 35 and work rolls 31, 32 againstthe metal wire stock 15. As the work rolls move inwardly and engage thewire stock, the spiralling relation of the skewed rolls relative to thewire pulls the wire through the machine, and this action proceeds untilthe coil is exhausted. Fresh coils of wire stock may be knurled withoutfurther regulation of the apparatus except the requirement ofrepositioning the guide rolls as each new coil is started. If the wirestock is of substantially uniform diameter, this becomes unnecessary.

Thus, in accordance with my invention, I have processed through a coilof cold-drawn 18% chromium, 8% nickel stainless steel wire of 0.086 inchdiameter. This wire was knurled in an indented spiral design in amachine according to my invention at a head speed of about 3509 R. P. M.The working rolls drew the wire through the revolving head at a speed of45 feet per minute. The product, a wire of the character heretoforedescribed in this specification, was then fabricated without difficultyinto 1 /2 inch headed nails, in a standard nail machine. Tested inasbestos shingles, the nails exhibited holding powergreatly in excess ofthe tenacity offered by standard siding nails formed of similarmaterial, the holding qualities being ample to satisfy all therequirements of the art.

And it will be seen from the foregoing that, in accordance with myinvention, it is possible to produce metal wire stock of stainless steel'and generally similar refractory metals which can be fabricated intometal fasteners displaying a high degree of tenacity even when heavilyloaded while existing in short operational lengths. Also that I haveprovided both a method and apparatus which are simple in themselves,economical of production and in operation and maintenance, and in whichthe machine displays long useful life with certainty in operation, andwhich can be adjusted for varying operational conditions with-a minimumof supervision and attendance, and

which produces a wide variety of patterns on the metal Wire stock. Boththe method and the apparatus are sufficiently rapid to permit successfulentry into the highly competitive field of producing metal fasteners,and to permit the combination for the first time of the well recognizedand highly desirable'qualities of stainless steel wire with tenaciousholding qualities. All these and many others, highly desirable objectsand advantages, attend upon the practice of my invention.

Since many embodiments of my invention will suggest themselvesto thoseskilled in the art, once the broad .aspects are disclosed, I intend theforegoing disclosure to'be construed merely as illustratively and not byWay of limitation.

I claim:

1. A machine for'knurling metal wire stock, comprising, in combination,guide means for directing the wire stock towards a revolving head whilerestraining the wire against twisting, and a revolving head throughwhich the wire stock passes having knurling means thereon means forestablishing the force with which the knurling element The severity ofthese thereof is applied against the wire stock, means establishing theskew angle of the knurling means relative to the wire stock, and meansresponsive to and proportional to the speed of revolution of saidrevolving head for compelling said forcing means against the wire stock.

2. A machine for knurling metal wire stock, comprising, in combination,guide means for guiding the metal wire in its linear path towards arevolving head and for restraining the wire against twisting, and arevolving head into which the wire stock feeds from the guide means,said revolving head comprising paired knurling rolls disposed onopposite sides of said wire stock, holders for said rolls in which thelatter are rotatable, means for forcing said roll holders bodily towardssaid wire stock, speed-responsive means for compelling said forcingmeans towards said wire stock as an incident to and proportional to thespeed of revolution of said revolving head, and means for revolving saidrevolving head.

3. A machine for knurling metal wire stock, comprising, in combination,guide means for guiding the metal wire 1n its linear path towards arevolving head and for restraining the wire against twisting, arevolving head into which the wire stock feeds from the guide means, andmeans fast to said guide means for revolving said revolving head, saidrevolving head comprising paired knurling rolls disposed on oppositesides of said wire stock, holders for said rolls in which the latter arerotatable, means for forcing said roll holders bodily towards said wirestock, speed-responsive means for compelling said forcing means towardssaid wire stock, as an incident to and proportional to the speed ofrevolution of said revolving head, inlet and outlet guide trunnions forsaid revolving head through which the wire stock passes in its passageto and from the revolving head.

4. A knurling machine for stainless steel wire stock,

comprising a base plate, bearing standards extending upwardly from saidbase plate, a revolvable head having hollow spindles rotatably carriedin said bearings and through which hollow spindles the wire stockpasses,

means fast to one of the spindles of said head whereby rotational forcemay be imparted to the revolving head, and means for rotating therevolving head, said head com prising side members fast to said inletand outlet spindles, paired counter-weight levers and cooperatingadjustable counter-weights thereon, carried between said side membersand responsive to centrifugal action, separating elements disposedbetween said side members and said counter-weight levers, pressureblocks disposed between the working head of each said counter-weightlever and the adjacent separator element, means extending between saidside members and cooperating with said counterweight levers and saidseparator elements for constraining said separator elements for movementin a radial direction towards and away from the wire stock passingcentrally through the axis of said revolving head under the impellingaction of said counter-weight levers, a knurling roll yoke carried onein each said pressure element and longitudinally and angularlyadjustable thereto, a knurling roll mounted for rotation in each saidyoke for knurling the metal wire in a spiral pattern, the variation inthe rotational speed of said revolvable head, in the position of thecounter-weights along the counter-weight levers, and in the longitudinaland angular adjustment of the roll yokes relative to the pressure blocksbringing about corresponding variations in the knurled pattern on tthewire stock, in the pitch of the spiral pattern produced thereon, and inthe linear speed of the wire stock through the revolving head.

5. In knurling apparatus for metal wire stock, a revolving headcomprising in combination, centrally bored mem bers, anti-frictionbearings supporting the same for axial rotation, diametrically opposedand paired counter-weight levers pivotally carried between said members,spacing members also carried between said members and disposed betweensaid counter-weight levers, paired pressure blocks in said revolvinghead carried loosely between said spacing members and saidcounter-weight levers and adapted to be forced inwardly by said levers,roll yokes rotatably carried one by each of said pressure member, andknurling rolls carried in said yoke members, the said yoke members beingadjustable both longitudinally and angularly relative to said pressureblocks.

6. A revolving head for knurling metal wire stock, comprising incombination, two centrally bored members, a support for the sameincluding anti-friction bearings,

; diametrically opposed and paired counter-weight levers pivotallycarried between said members, and having adjustable counter-weightsthereon, spacing members also carried between said two members anddisposed between said counter-weight levers, paired pressure blocks insaid revolving head carried loosely between said spacing members andsaid counter-weight levers and being constrained thereby to linearmotion towards and away from said wire stock under the impelling actionof said counterweight levers, roll yokes rotatably carried one by eachof said pressure member, and knurling rolls carried in said yoke memberswhich said yoke members are adjustable both longitudinally and angularlyrelative to said pressure blocks, and means for rotating said revolvinghead, said yoke and pressure blocks having graduations thereon forfacilitating angular adjustment of the yoke relative to said pressureblocks.

7. A revolving head for knurling metal wire stock, comprising, incombination, a pair of centrally bored members, a support for the sameincluding anti-friction bearings, diametrically opposed and pairedcounterweight levers pivotally carried between said members and havingcounter-weights adjustable along the length thereof with graduationsthereon for facilitating the adjustment of the counter-weights, spacingmembers also carried between said pair of members and disposed betweensaid counter-weight levers, paired pressure blocks in said revolvinghead carried loosely between said spacing members and saidcounter-weight levers and being constrained thereby to linear motiontowards and away from said wire stock under the impelling action of saidcounter-weight levers, roll yokes rotatably carried one by each of saidpressure member, and knurling rolls carried in said yoke members, thesaid yoke members being adjustable both longitudinally and angularlyrelative to said pressure blocks, and said yoke and pressure blockshaving graduations thereon for facilitating angular adjustment of theyoke relative to said pressure blocks.

References Cited in the file of this patent UNITED STATES PATENTS 60,067Sanford Nov. 27, 1866 145,285 Dudley Dec. 9, 1873 204,149 Heckmann May28, 1878 206,688 Richardson Aug. 6, 1878 234,222 Atwood Nov. 9, 1880318,566 Jones May 26, 1885 413,625 Moore Oct. 25, 1889 415,880 Patt Nov.26, 1889 455,336 Johnston July 7, 1891 855,658 OBrien June 4, 1907960,769 Armstrong June 7, 1910 1,365,386 Djidics Jan. 11, 1921 1,394,716Davies Oct. 25, 1921 1,546,091 Lewis July 14, 1925

